Surgical instruments for preparing a patient&#39;s tibia to receive an implant

ABSTRACT

An orthopaedic surgical instrument system that includes an orthopaedic surgical instrument adapted to be positioned on a proximal end of a patient&#39;s tibia, and a tibial bearing trial assembly, and a tibial evaluation component, and a tibial base trial component configured to be coupled to the orthopaedic surgical instrument. A tibial evaluation component includes a base plate and a generally Y-shaped posterior buttress extending upwardly from a superior surface of the base plate, such that the posterior buttress of the insert component is configured to be received in the opening of the tibial bearing trial assembly to prevent rotation of the tibial bearing trial component relative to the tibial base trial component.

This application is a divisional application and claims priority to U.S.patent application Ser. No. 14/886,923, now U.S. Pat. No. 10,537,445,the entirety of which is expressly incorporated herein by reference.

CROSS-REFERENCE

Cross-reference is made to U.S. patent application Ser. No. 14/886,796,now U.S. Pat. No. 10,195,056, entitled “METHOD FOR PREPARING A PATIENT′STIBIA TO RECEIVE AN IMPLANT” by Thomas E. Wogoman et al. and filed onOct. 19, 2015, U.S. patent application Ser. No. 13/530,771, now U.S.Pat. No. 8,986,390, entitled “METHOD OF TRIALING A KNEE PROSTHESIS” byThomas E. Wogoman et al. and filed on Jun. 22, 2012, U.S. patentapplication Ser. No. 13/530,662, now U.S. Pat. No. 8,951,301, entitled“METHOD OF USING A TRIALING SYSTEM FOR A KNEE PROSTHESIS” by Thomas E.Wogoman et al. and filed on Jun. 22, 2012, U.S. patent application Ser.No. 13/530,649, now U.S. Pat. No. 8,968,412, entitled “TRIALING SYSTEMFOR A KNEE PROSTHESIS AND METHOD OF USE” by Thomas E. Wogoman et al. andfiled on Jun. 22, 2012, and U.S. patent application Ser. No. 14/265,960,now U.S. Pat. No. 9,861,491, entitled “TIBIAL TRIAL SYSTEM FOR A KNEEPROSTHESIS” by David W. Waite et al. and filed on Apr. 30, 2014, each ofwhich is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to surgical instruments used with apatient's tibia.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.A typical knee prosthesis includes a patella prosthetic component, atibial tray, a femoral component, and a polymer insert or bearingpositioned between the tibial tray and the femoral component. Femoralcomponents are designed to be attached to a surgically-prepared distalend of a patient's femur. Tibial trays are designed to be attached to asurgically-prepared proximal end of a patient's tibia.

To facilitate the replacement of the natural joint with the kneeprosthesis, orthopaedic surgeons use a variety of orthopaedic surgicalinstruments such as, for example, prosthetic trial components, cuttingblocks, drill guides, milling guides, and other surgical instruments.Prosthetic trial components, such as, for example, a femoral trialcomponent and a tibial bearing trial component, are used to size andselect the components of the knee prosthesis that will replace thepatient's natural joint. A procedure that utilizes the trial componentsto size and select the components of the knee prosthesis is oftenreferred to as a trial reduction.

SUMMARY

According to one aspect of the disclosure, an orthopaedic surgicalinstrument system for use during a surgical procedure to implant anorthopaedic knee prosthesis is disclosed. The system includes a tibialbase trial component adapted to be positioned on a surgically-preparedproximal end of a patient's tibia, an insert component shaped to bereceived in an opening defined in the tibial base trial component, and atibial bearing trial component having an inner sidewall that defines anopening therein. The insert component comprises a base plate and agenerally Y-shaped posterior buttress extending upwardly from a superiorsurface of the base plate. The posterior buttress of the insertcomponent is configured to be received in the opening of the tibialbearing trial component to prevent rotation of the tibial bearing trialcomponent relative to the tibial base trial component.

In some embodiments, the posterior buttress may include a postpositioned adjacent to a posterior edge of the base plate and a pair ofarms extending posteriorly from the post and outwardly from theposterior edge of the base plate.

In some embodiments, the pair of arms may include a first arm and asecond arm. A first imaginary line may extend along a lateral-most edgeof the first arm of the posterior buttress. A second imaginary line mayextend along a medial-most edge of the second arm of the posteriorbuttress and intersect the first imaginary line to define an angle ofintersection therebetween. The angle of intersection may be between45-145°.

Additionally, in some embodiments, the insert component may furthercomprise an anterior buttress extending outwardly from an anterior edgeof the base plate. The anterior buttress may include a pair of armsextending anteriorly from the anterior edge of the base plate and a tabextending superiorly from an anterior end of each arm.

In some embodiments, the system may include a retention mechanism tosecure the insert component to the tibial base trial component. Theretention mechanism may comprise an annular rim extending outwardly fromthe base plate of the insert component, and a groove defined in thetibial base trial component sized to receive the annular rim of theinsert component.

In some embodiments, the insert component may include a first prongextending medially from the base plate and a second prong extendinglaterally from the base plate. Additionally, in some embodiments, theinsert component may include a keel configured to extend inferiorly andoutwardly from the opening in the tibial base trial component when theinsert component is received in the opening defined in the tibial basetrial component.

In some embodiments, the tibial base trial component may include aninferior surface positioned opposite the superior surface. The openingin the tibial base trial component may be defined by an inner wallextending inwardly from the superior surface to a shelf surfacepositioned between the superior surface and the inferior surface. Anumber of fixation pinholes may extend through a posterior section ofthe shelf surface and the inferior surface.

In some embodiments, the system may also comprise a fixation pinincluding a head including an inferior surface configured to engage theposterior section of the shelf surface and a superior surface positionedopposite the inferior surface. The fixation pin may also include a shaftextending from the inferior surface of the head that is sized to extendinferiorly from at least one of the fixation pinholes defined in thetibial base trial component. When the inferior surface of the head ofthe fixation pin is engaged with the posterior section of the shelfsurface, the superior surface of the head of the fixation pin may beconfigured to be positioned at or below an imaginary plane defined bythe superior surface of the tibial base trial component.

In some embodiments, the system may comprise a pin extraction toolcomprising a stationary member, a pivoting member pivotally coupled tothe handle, and a receiving end including a first jaw extending from thestationary member and a second jaw extending from the pivoting member.The first jaw and the second jaw may be configured to engage the head ofthe fixation pin. The pivoting member is pivotable between a closedposition in which the first jaw and the second jaw define a pocket sizedto retain the head of the fixation pin, and an open position in whichthe first jaw and the second jaw are spaced apart to permit the head ofthe fixation pin to be disengaged from the first jaw and the second jaw.

In some embodiments, the insert component may be a first insertcomponent. The system may further comprise a second insert componentconfigured to be separately received in the opening defined in thetibial base trial component in place of the first insert component. Thesecond insert component may have a central post, and a superior surfaceof the central post may have a ramp surface defined therein. The rampsurface may incline superiorly in an anterior-to-posterior direction.

According to another aspect, an orthopaedic surgical instrument systemfor use during a surgical procedure to implant an orthopaedic kneeprosthesis comprises a tibial base trial component including a superiorsurface, an inferior surface positioned opposite the superior surfacethat is adapted to be positioned on a surgically-prepared proximal endof a patient's tibia, an opening being defined by an inner wallextending inwardly from the superior surface to a shelf surfacepositioned between the superior surface and the inferior surface, and anumber of fixation pinholes extending through a posterior section of theshelf surface and the inferior surface of the tibial base trialcomponent. The system also comprises an insert component shaped to bereceived in the opening defined in the tibial base trial component, anda tibial bearing trial component having an inner sidewall that definesan opening therein. The insert component comprises a base plate and aposterior buttress extending upwardly from a superior surface of thebase plate. The posterior buttress of the insert component is configuredto be received in the opening of the tibial bearing trial component toprevent rotation of the tibial bearing trial component relative to thetibial base trial component.

In some embodiments, the insert component may further comprise ananterior buttress extending outwardly from an anterior edge of the baseplate. Additionally, in some embodiments, the anterior buttress of theinsert component may include a pair of arms extending anteriorly fromthe anterior edge of the base plate and a tab extending superiorly froman anterior end of each arm.

In some embodiments, the insert component may be a first insertcomponent of a plurality of insert components. Each insert component maybe shaped to be separately received in the opening defined in the tibialbase trial component. A number of the insert components may include abase plate and a keel extending inferiorly from the base plate.Additionally, in some embodiments, the keel may include a pair of spikesextending inferiorly from the base plate.

According to another aspect, an orthopaedic surgical instrument systemcomprises a tibial base trial component including a superior surface, aninferior surface positioned opposite the superior surface that isadapted to be positioned on a surgically-prepared proximal end of apatient's tibia, an opening being defined by an inner wall extendinginwardly from the superior surface to a shelf surface positioned betweenthe superior surface and the inferior surface, and a fixation pinholeextending through a posterior section of the shelf surface and theinferior surface of the tibial base trial component. The system alsocomprises a fixation pin including a head and a shaft extendinginferiorly from the head that is sized to be received in the fixationpinhole of the tibial base trial component, an insert component shapedto be received in the opening defined in the tibial base trialcomponent, and a tibial bearing trial component adapted to be positionedon the insert component. The head of the fixation pin is sized to be ator below the superior surface of the tibial base trial component whenthe head is engaged with the shelf surface.

In some embodiments, the system may further comprise a surgicalinstrument including a pair of jaws configured to selectively engage thehead of the fixation pin, the pair of jaws comprising a first jawincluding a semi-circular flange and a second jaw including an arcedflange extending less than 180 degrees.

According to another aspect of the disclosure, a method of trialingprosthetic components of a knee prosthesis is disclosed. The methodcomprises positioning a tibial base trial component on asurgically-prepared proximal end of a patient's tibia, positioning afemoral trial component on a surgically-prepared distal end of apatient's femur, inserting an insert component into an opening definedin the tibial base trial component, advancing a first fixation pin intoa posterior fixation pinhole defined in the tibial base trial component,positioning a tibial bearing trial component over the insert component,between the tibial base trial component and the femoral trial component,and moving the patient's tibia between extension and flexion with thefemoral trial component engaged with the tibial bearing trial componentsuch that the tibial base trial component rotates on the proximal end ofthe patient's tibia about the first fixation pin. The method alsocomprises advancing a second fixation pin into an anterior fixationpinhole of the tibial base trial component to prevent rotation of thetibial base trial component.

In some embodiments, positioning the tibial bearing trial component overthe insert component may include advancing the tibial bearing trialcomponent in a posterior direction into a gap defined between the tibialbase trial component and the femoral trial component.

Additionally, in some embodiments, positioning the tibial bearing trialcomponent over the insert component may further include securing thetibial bearing trial component to the insert component to preventrelative movement between the tibial bearing trial component and thetibial base trial component.

In some embodiments, securing the tibial bearing trial component to theinsert component may include engaging the tibial bearing trial componentwith a posterior buttress of the insert component. The posteriorbuttress may include a post sized be received in an opening defined inthe tibial bearing trial component and a pair of arms extendingposteriorly from the post.

In some embodiments, securing the tibial bearing trial component to theinsert component may further include engaging the tibial bearing trialcomponent with an anterior buttress of the insert component.

Additionally, in some embodiments, advancing the first fixation pin intothe posterior fixation pinhole may include positioning a head of thefirst fixation pin at or below a superior surface of the tibial bearingtrial component, and positioning the tibial bearing trial component overthe insert component may include engaging the tibial bearing trialcomponent with the superior surface of the tibial bearing trialcomponent.

In some embodiments, the method may also comprise selecting the insertcomponent from a plurality of insert components. The plurality of insertcomponents may include a first insert component configured to permit thetibial bearing trial component to rotate relative to the insertcomponent and a second insert component configured to prevent the tibialbearing trial component from rotating relative to the insert component.

Additionally, in some embodiments, the method may also compriseinserting a keel punch into the patient's tibia after advancing thesecond fixation pin into the anterior fixation pinhole to define asurgically-prepared opening.

According to another aspect, a method of surgically preparing apatient's bone to receive a knee prosthesis comprises positioning atibial base trial component on a surgically-prepared proximal end of apatient's tibia, positioning a femoral trial component on asurgically-prepared distal end of a patient's femur, inserting an insertcomponent into an opening defined in the tibial base trial component,advancing a tibial bearing trial component in a posterior direction intoa gap defined between the tibial base trial component and the femoraltrial component, and securing the tibial bearing trial component to theinsert component to prevent relative movement between the tibial bearingtrial component and the tibial base trial component by engaging thetibial bearing trial component with a posterior buttress of the insertcomponent that includes a post sized be received in an opening definedin the tibial bearing trial component and a pair of arms extendingposteriorly from the post.

In some embodiments, securing the tibial bearing trial component to theinsert component may further include engaging the tibial bearing trialcomponent with an anterior buttress of the insert component.Additionally, inserting the insert component into the opening defined inthe tibial base trial component may include inserting a keel of theinsert component through the opening defined in the tibial base trialcomponent and into the surgically-prepared proximal end of the patient'stibia.

In some embodiments, the method may include moving the patient's tibiabetween extension and flexion with the femoral trial component engagedwith the tibial bearing trial component such that the tibial base trialcomponent rotates on the proximal end of the patient's tibia. The methodmay further include advancing a fixation pin into a posterior fixationpinhole defined in the tibial base trial component. The tibial basetrial component may rotate on the proximal end of the patient's tibiaabout the fixation pin as the patient's tibia is moved between extensionand flexion.

In some embodiments, the method may include advancing a second fixationpin into an anterior fixation pinhole of the tibial base trial componentto prevent rotation of the tibial base trial component.

Additionally, in some embodiments, the method may include removing theinsert component from the tibial base trial component after advancingthe second fixation pin into the anterior fixation pinhole, andinserting a keel punch into the patient's tibia to define asurgically-prepared opening.

In some embodiments, inserting the insert component into an openingdefined in the tibial base trial component may include engaging aretention ring of the insert component with the tibial base trialcomponent.

According to another aspect, a method of surgically preparing apatient's bone to receive a knee prosthesis comprises selecting a tibialbearing trial component, and selecting an insert component from aplurality of insert components. The plurality of insert componentsincludes a first insert component configured to permit the tibialbearing trial component to rotate relative to the insert component and asecond insert component configured to prevent the tibial bearing trialcomponent from rotating relative to the insert component. The methodfurther comprises positioning a tibial base trial component on asurgically-prepared proximal end of a patient's tibia and advancing thetibial bearing trial component in a posterior direction to position thetibial bearing trial component over the selected insert component. Whenthe selected insert component is the first insert component, the methodincludes moving the patient's tibia between extension and flexion suchthat the tibial bearing trial component rotates on the tibial base trialcomponent. When the selected insert component is the second insertcomponent, the method includes advancing a first fixation pin into aposterior fixation pinhole defined in the tibial base trial component,and moving the patient's tibia between extension and flexion such thatthe tibial base trial component rotates on the proximal end of thepatient's tibia about the first fixation pin.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is an exploded perspective view of an orthopaedic surgicalinstrument system;

FIG. 2 is an exploded perspective view of a tibial base trial component,a number of tibial evaluation components, and a number of tibial bearingtrial components of the orthopaedic surgical instrument system of FIG.1;

FIG. 3 is a perspective view of a tibial base trial component of theorthopaedic surgical instrument system of FIGS. 1 and 2;

FIG. 4 is a top plan view of the tibial base trial component of FIG. 3;

FIG. 5 is a perspective view of one of the tibial evaluation componentsof FIG. 2;

FIG. 6 is a perspective view of another tibial evaluation component ofFIG. 2;

FIG. 7 is a perspective view of another tibial evaluation component ofFIG. 2;

FIG. 8 is a top plan view of the tibial evaluation component of FIG. 7;

FIG. 9 is a bottom view of the tibial evaluation component of FIG. 7;

FIG. 10 is a perspective view of another tibial evaluation component ofFIG. 2;

FIG. 11 is a top plan view of the tibial evaluation component of FIG.10;

FIG. 12 is a perspective view of a posterior fixation pin and ananterior fixation pin;

FIG. 13 is a perspective view of one of the fixation pin and a pinextraction tool of the orthopaedic surgical instrument system of FIG. 1;

FIG. 14 is a front elevation view showing the pin extraction tool ofFIG. 11 in a closed position;

FIG. 15 is a view similar to FIG. 12 showing the pin extraction tool inan open position; and

FIGS. 16-22 is views of a patient's femur, tibia, and the orthopaedicsurgical instrument system of FIG. 1 as the orthopaedic surgicalinstrument system is used in the performance of a surgical procedure toimplant a knee prosthesis.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopaedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring to FIGS. 1-15, an orthopaedic surgical instrument system 10(hereinafter system 10) is shown. The system 10 is used during jointarthroplasty procedures, such as a total knee replacement procedure. Itshould be appreciated, however, that although the system 10 is describedbelow in regard to the performance of a total knee replacementprocedure, certain concepts associated with the system 10 may beutilized in replacement procedures of numerous other joints throughoutthe body.

As shown in FIGS. 1-2, the system 10 has a number of trial components12, including a tibial base trial component 14, a number of insertcomponents 16, a number of tibial bearing trial components 18, and afemoral trial component 20. In the illustrative embodiment, the system10 also includes a number of fixation pins 250, a tibial keel punch 374,and a number of other surgical tools, such as, for example, an alignmenthandle (not shown), an impaction handle 372, and a fixation pinextraction tool 300, which are used to manipulate the trial components12, the fixation pins 250, and the other surgical instruments during theperformance of an orthopaedic surgical procedure, as described ingreater detail below.

The system 10 may be utilized to size and select the prostheticcomponents of a knee prosthesis that will replace the patient's naturaljoint. To do so, the femoral trial component 20 is attached to asurgically-prepared distal end 406 of a patient's femur 404 (see FIGS.18-20), whereas the tibial base trial component 14 is attached to asurgically-prepared proximal end 402 of a patient's tibia 400 (see FIGS.18-20). As shown in FIG. 1, one of the insert components 16 may bepositioned in the tibial base trial component 14. Further, one of thetibial bearing trial components 18 may be positioned between the femoraltrial component 20 and the tibial base trial component 14. As describedin greater detail below, the surgeon uses the system 10 during asurgical procedure in, for example, a trial reduction process, todetermine the type and configuration of each of the various types ofprosthetic components that are to be implanted and to surgically preparethe proximal end 402 of a patient's tibia 400 for implantation of atibial prosthetic component.

Referring to FIG. 2, a number of tibial bearing trial components 18 ofthe system 10 are shown. In the illustrative embodiment, each tibialbearing trial component 18 is a multi-piece assembly that is configuredto assist the surgeon in selecting a size and configuration of aprosthetic tibial bearing component of the knee prosthesis, as describedin greater detail below. In other embodiments, each tibial bearing trialcomponent 18 may be a unitary solid piece. The tibial bearing trialcomponents 18 may include fixed tibial bearing trial components ormobile tibial bearing trial components of different sizes for differentpatients. An exemplary fixed tibial bearing trial component is shown onthe left in FIG. 2. The term “fixed tibial bearing trial component” asused herein refers to the tibial bearing trial component 18 that isfixed in position relative to the tibial base trial component 14 when itis attached to a tibial base trial component 14. In other words, a fixedtibial bearing trial component is configured to not substantially rotateor move in the anterior-posterior direction or medial-lateral directionrelative to the tibial base trial component 14. Such a fixed bearingtrial component 18 may be embodied as a cruciate retaining trial, aposterior stabilized trial, a revision trial, or other surface trialconfiguration, per the surgeon's preference.

An exemplary mobile tibial bearing trial component is shown on the rightin FIG. 2. The term “mobile tibial bearing trial component” as usedherein refers to a tibial bearing trial component 18 that is permittedto rotate relative to the tibial base trial component 14 when it isattached a tibial base trial component 14. In other words, a mobiletibial bearing trial component is configured to substantially rotate ormove in the anterior-posterior direction or the medial-lateral directionrelative to the tibial base trial component 14. The mobile bearing trialcomponent 18 may be embodied as a cruciate retaining trial, a posteriorstabilized trial, a revision trial, or other surface trialconfiguration, per the surgeon's preference.

Regardless of the type of the tibial bearing trial component 18, thesame tibial base trial component 14 may be attached to thesurgically-prepared proximal end 402 of a patient's tibia 400. It shouldbe appreciated that the tibial base trial component 14, like the othertrial components 18, 20, may be formed in a number of different sizes toaccommodate bones of various sizes. As shown in FIGS. 3-4, the tibialbase trial component 14 includes a plate 22 having a superior surface24, an inferior surface 26, and an outer sidewall 28 extending betweenthe surfaces 24, 26. The plate 22 includes a plate opening 30 defined inthe superior surface 24. The plate opening 30 has a central opening 40and a pair of elongated openings 42 extending laterally and outwardlyfrom the central opening 40. An inner wall 44 extends downwardly fromthe plate opening 30 to define a passageway 46 through the plate 22. Theinner wall 44 includes an upper wall 48 and a lower wall 50 that isoffset or otherwise spaced inwardly from the upper wall 48. The upperwall 48 and the lower wall 50 cooperate to define a shelf surface 54positioned between the inferior surface 26 and the superior surface 24.As will be discussed in greater detail below, the configuration of thepassageway 46 permits the advancement of various surgical drills,punches, and other instruments into the proximal end 402 of thepatient's tibia 400.

The upper wall 48 of the plate 22 defines a number of slots 60 that arepositioned in an anterior aspect 62 and a posterior aspect 64 of theplate 22. As shown in FIGS. 3-4, the slots 60 include a pair of anteriorslots 66 that are positioned on each side of a lever-receiving notch 68defined in the outer sidewall 28 of the plate 22. A pair of posteriorslots 70 are positioned adjacent to each of the elongated openings 42.In the illustrative embodiment, all slots 60 extend downwardly from theplate opening 30 to the shelf surface 54.

As shown in FIGS. 3-4, the plate 22 of the tibial base trial component14 further includes a pair of posterior fixation pinholes 80 and a pairof anterior fixation pinholes 82 that receive corresponding fixationpins 250 to secure the tibial base trial component 14 to the patient'stibia 400. The posterior fixation pinholes 80 have the same shape as theanterior fixation pinholes 82 but are uniquely sized. In theillustrative embodiment, each posterior fixation pinhole 80 has amatching diameter, but each anterior fixation pinhole 82 has a diameterthat is greater than the diameters of the posterior fixation pinholes 80to prevent the surgeon from inserting the wrong fixation pin 250, asdescribed in greater detail below. It should be appreciated that inother embodiments the fixation pinholes 80, 82 may have rectangular,square, triangular, or other geometric shape. Additionally, although thefixation pinholes 80, 82 have the same shape in the illustrativeembodiment, it should be appreciated that in other embodiments eachopening may have a unique shape.

In the illustrative embodiment, the pair of posterior fixation pinholes80 is defined in the posterior aspect 64 of the tibial base trialcomponent 14 in a section of the shelf surface 54. Each posteriorfixation pinhole 80 extends downwardly from an opening defined in theshelf surface 54 through the inferior surface 26 of the plate 22 topermit a fixation pin to advance into a patient's bone. In theillustrative embodiment, each posterior fixation pinhole 80 includes apinhole upper wall 84 and a pinhole lower wall 86. The pinhole upperwall 84 extends downwardly from the shelf surface 54 to a pinhole shelfsurface 88. The pinhole lower wall 86 extends downwardly from thepinhole shelf surface 88 to the inferior surface 26 of the plate 22 ofthe tibial base trial component 14. As shown in FIGS. 3-4, eachposterior fixation pinhole 80 has a longitudinal axis 90 extendingperpendicular to the superior surface 24.

The pair of anterior fixation pinholes 82 are defined in a pair ofanterior tabs 100 extending anteriorly from the plate 22 of the tibialbase trial component 14. As shown in FIGS. 3-4, one tab 100 ispositioned on each side of the lever-receiving notch 68. Each anteriortab 100 has a superior inclined surface 102 that is angled relative tothe substantially planar superior surface 24 and substantially planarinferior surface 26. Each anterior fixation pinhole 82 is defined in thecenter of the inclined surface 102 by an inner sidewall 104 that extendsdownwardly from the inclined surface 102 of each anterior tab 100 to aninferior surface 106. Each anterior fixation pinhole 82 has alongitudinal axis 108 that extends perpendicular to the inclined surface102 and at an angle relative to the axes 90 of the posterior fixationpinholes 80. As shown in FIG. 4, the axes 108 of each anterior fixationpinhole 82 are angled relative to each other. In that way, a fixationpin positioned in either anterior fixation pinhole 82 is engaged withthe proximal end 402 of the patient's tibia 400 at an oblique angle, aswill be described in detail below.

Returning to FIG. 2, the system 10 includes a number of insertcomponents 16 of the system 10, which are selected according based onthe type of the tibial bearing trial component 18 selected for aparticular patient. Specific exemplary insert components 16 are shownand described in detail in FIGS. 5-11, as will be described in greaterdetail below. Generally, the insert component 16 is embodied as a tibialevaluation component or “evaluation bullet.” Each tibial evaluationcomponent 16 is configured to be positioned separately in the plateopening 30 of the tibial base trial component 14. Each tibial evaluationcomponent 16 has a base plate 120 having a central platform 122 and apair of prongs 124 that extend outwardly from the central platform 122.A post 126 extends upwardly from the central platform 122 of each tibialevaluation component 16.

As shown in FIG. 2, the tibial evaluation components 16 include a pairof mobile bearing evaluation components 132, 134, which may be used withthe mobile tibial bearing trial component, and a pair of the fixedbearing evaluation components 136, 138, which may be used with the fixedtibial bearing trial component. As shown in detail in FIG. 5, the mobilebearing evaluation component 132 includes a pair of mounting spikes 140that extend downwardly from the prongs 124. Each spike 140 includes anupper cylindrical section 142 and a pointed conical tip 144 configuredto engage the proximal end 402 of the patient's tibia 400, therebytemporarily securing the tibial evaluation component 132 and the tibialbase trial component 14 to the proximal end 402 of the patient's tibia400. In that way, the assembly formed by the components 14, 132 may beprevented from moving relative to the patient's tibia. The post 126 ofthe mobile bearing evaluation component 132 includes a connector 148that is formed in its superior end. The connector 148 is configured toreceive a locking flange associated with an impaction handle 372 so asto secure the tibial evaluation component 16 to the impaction handle372. The connector 148 includes a flange 150 that extends anteriorlyaway from the longitudinal axis of the post 126. The flange 150 has aramp surface 152 defined therein. In particular, an inferior surface 154of the flange 150 extends substantially parallel to a superior surface156 of the tibial evaluation component's base plate 120, whereas theflange's superior surface 158 inclines superiorly in theanterior-to-posterior direction. The ramp surface 152 facilitatesinstallation of the tibial bearing trial assembly and is furtherdescribed in co-pending U.S. patent application Ser. No. 14/265,960,entitled “TIBIAL TRIAL SYSTEM FOR A KNEE PROSTHESIS” by David Waite etal. and filed on Apr. 30, 2014, which is incorporated herein byreference.

Referring now to FIG. 6, another mobile evaluation component 134 isshown. The evaluation component 134 shares many common features with thetibial evaluation component 132, and the same reference numbers will beused to describe those common features. Additionally, the component 134,like the other evaluation components 16, includes a base plate 120having a central platform 122 and a pair of prongs 124 that extendoutwardly from the central platform 122. A post 126 extends upwardlyfrom the central platform 122 of each tibial evaluation component 16and, like the other mobile evaluation component 132, also includes aconnector 148 that is formed in its superior end. The connector 148 isconfigured to receive a locking flange associated with the impactionhandle 372. The connector 148 includes a flange 150 that extendsanteriorly away from the longitudinal axis of the post 126. The flange150 has a ramp surface 152 defined therein. In particular, an inferiorsurface 154 of the flange 150 extends substantially parallel to asuperior surface 156 of the tibial evaluation component's base plate120, whereas the flange's superior surface 158 inclines superiorly inthe anterior-to-posterior direction.

The mobile evaluation component 134 also includes a sleeve 160 thatextends downwardly from the central platform 122 and the prongs 124. Thesleeve 160 includes a central stem 162 sized to be received in thecentral opening 40 of the tibial base trial component 14. The sleeve 160further includes a pair of prongs 164 that extend outwardly from thecentral stem 162, which are sized to be received in the elongatedopenings 42 of the tibial base trial component 14. As described ingreater detail below, the sleeve 160 is sized to extend through thetibial base trial component 14 and into a surgically-prepared opening inthe patient's tibia and thereby prevent the components 14, 134 fromrotating on the patient's tibia.

Returning to FIG. 2, the tibial evaluation components 16 also includethe pair of fixed bearing elevation components 136, 138. Each of theevaluation components 136, 138 has a base plate 120 having a centralplatform 122 and a pair of prongs 124 that extend outwardly from thecentral platform 122. A post 126 extends upwardly from the centralplatform 122 of each tibial evaluation component 16. In the illustrativeembodiment, the post 126 of each of the evaluation components 136, 138is included in a posterior buttress 170. In addition to the post 126,each posterior buttress 170 includes a pair of arms 172, 174 that extendposteriorly from the post 126 to cantilevered tips 176, 178. Each of theevaluation components 136, 138 also includes an anterior buttress 180.As described in greater detail below, the buttresses 170, 180 cooperateto prevent rotation and movement of the fixed bearing trial component 18relative to the tibial base trial component 14.

Referring now to FIGS. 7-9, the fixed evaluation component 136 isillustratively spikeless. As a result, when the fixed evaluationcomponent 136 is attached to the tibial base trial component 14 on apatient's tibia, the assembly is permitted move relative to thepatient's tibia unless restrained by a fixation pin 250. As describedabove, the evaluation component 136 includes a base plate 120 that has asuperior surface 182 and an inferior surface 184 positioned opposite thesuperior surface. An aperture 186 extends through the surfaces 182, 184in the central platform 122 of the base plate 120. In the illustrativeembodiment, the aperture 186 is sized to receive a tip (not shown) of aremoval tool to detach the evaluation component 136 from the tibial basetrial component 14.

As described above, the evaluation component 136 also has a posteriorbuttress 170 that includes a post 126 and a pair of arms 172, 174extending posteriorly from the post 126 to cantilevered tips 176, 178,respectively. As shown in FIG. 7, the post 126 is positioned on theposterior edge 188 of the base plate 120. The arm 172 defines alateral-most sidewall 190 of the posterior buttress 170, which extendsalong a straight imaginary line 192. The other arm 174 defines amedial-most sidewall 194 of the posterior buttress 170, which extendsalong another straight imaginary line 196. As shown in FIG. 8, the pairof arms 172, 174 are positioned such that the imaginary line 192intersects the other imaginary line 196 to define an angle α. In theillustrative embodiment, the angle a may have a magnitude of between 45and 145 degrees, thereby giving the posterior buttress 170 a generallyY-shape.

As described above, the evaluation component 136 also includes ananterior buttress 180. As shown in FIGS. 7-8, the anterior buttress 180includes a pair of arms 200, 202, which extend anteriorly from theanterior edge 204 of the base plate 120 to cantilevered end 206, 208,respectively. Each arm 200, 202 has a tab 210 that extends superiorlyfrom the respective ends 206, 208 of the arms 200, 202. In theillustrative embodiment, the tabs 210, post 126, and arms 172, 174cooperate to define a retention mechanism that engages a fixed bearingtrial component 18 and prevents rotation and movement of the fixedbearing trial component 18 relative to the tibial base trial component14.

Referring now to FIG. 9, the base plate 120 of the tibial evaluationcomponent 126 further includes an attachment mechanism 220 to secure theevaluation component 126 to the tibial base trial component 14. In theillustrative embodiment, the attachment mechanism 220 includes aretention ring 222 and a pair of blocks 224 extending downwardly fromthe base plate 120. The retention ring 222 extends from the inferiorsurface 184 of the central platform 122, and each of the blocks 224 ispositioned on the inferior surface 184 of each prong 124. When thetibial evaluation component 136 is seated on the tibial base trialcomponent 14, the central platform 122 of the tibial evaluationcomponent 126 is received in the central opening 40 of the tibial basetrial component 14, and the prongs 124 are received in the elongatedopenings 42 of the tibial base trial component 14.

As shown in FIG. 3, the tibial base trial component 14 includes anannular flange 230 that extends around the central opening 40. When thetibial evaluation component 136 is seated on the tibial base trialcomponent 14, the retention ring 222 of the evaluation component 126extends through the central opening 40 of the tibial base trialcomponent 14 and engages the annular flange 230, thereby securing thecomponents 14, 136 together. Further, the pair of blocks 224 extend intothe elongated openings 42 of the tibial base trial component 14. Theretention ring 222 and blocks 224 are sized to not extend beyond theinferior surface 26 of the tibial base trial component 14 such that whenthe fixed evaluation component 136 is attached to the tibial base trialcomponent 14 on a patient's tibia 400, the assembly is permitted to moverelative to the patient's tibia 400 unless restrained by a fixation pin250.

As described above, the instrument system 10 also includes another fixedevaluation component 138, which is shown in FIGS. 10-11. The evaluationcomponent 138 shares many common features with the other evaluationcomponents 132, 134, 136, and the same reference numbers will be used todescribe those common features. As described above, the evaluationcomponent 138 includes a base plate 120 that has a superior surface 182and an inferior surface 184 positioned opposite the superior surface. Anclosed aperture 240 is defined in the superior surface 182 of thecentral platform 122 of the base plate 120. In the illustrativeembodiment, the aperture 240 is sized to receive a tip of a removaltool, such as, for example, impaction handle 372, to detach theevaluation component 138 from the tibial base trial component 14.

As described above, the evaluation component 136 also has a posteriorbuttress 170 that includes a post 126 and a pair of arms 172, 174extending posteriorly from the post 126 to cantilevered tips 176, 178,respectively. As shown in FIG. 10, the post 126 is positioned on theposterior edge 188 of the base plate 120. The arm 172 defines alateral-most sidewall 190 of the posterior buttress 170, which extendsalong a straight imaginary line 192. The other arm 174 defines amedial-most sidewall 194 of the posterior buttress 170, which extendsalong another straight imaginary line 196. As shown in FIG. 11, the pairof arms 172, 174 are positioned such that the imaginary line 192intersects the other imaginary line 196 to define an angle α. In theillustrative embodiment, the angle a may have a magnitude of between 45and 145 degrees, thereby giving the posterior buttress 170 a generallyY-shape.

As described above, the evaluation component 138 also includes ananterior buttress 180. As shown in FIGS. 10-11, the anterior buttress180 includes a pair of arms 200, 202, which extend anteriorly from theanterior edge 204 of the base plate 120 to cantilevered end 206, 208,respectively. Each arm 200, 202 has a tab 210 that extends superiorlyfrom the respective ends 206, 208 of the arms 200, 202. In theillustrative embodiment, the tabs 210, post 126, and arms 172, 174cooperate to define a retention mechanism that engages a fixed bearingtrial component 18 and prevents rotation and movement of the fixedbearing trial component 18 relative to the tibial base trial component14.

Like the mobile evaluation components 132, 134, the evaluation component138 also includes a connector 148 that is formed at the superior end ofthe post 126. The connector 148 is configured to receive a lockingflange associated with the impaction handle 372. In the illustrativeembodiment, the connector 148 includes a flange 150 that extendsanteriorly away from the longitudinal axis of the post 126. As shown inFIGS. 10-11, the flange 150 is positioned above the closed aperture 240.

The fixed evaluation component 138 also includes a sleeve 160 thatextends downwardly from its central platform 122 and prongs 124. Thesleeve 160 includes a central stem 162 sized to be received in thecentral opening 40 of the tibial base trial component 14. The sleeve 160further includes a pair of prongs 164 that extend outwardly from thecentral stem 162, which are sized to be received in the elongatedopenings 42 of the tibial base trial component 14. As described ingreater detail below, the sleeve 160 is sized to extend through thetibial base trial component 14 and into a surgically-prepared opening inthe patient's tibia and thereby prevent the components 14, 138 fromrotating on the patient's tibia.

As described above, the surgical instrument system 10 also includes anumber of fixation pins 250 for use with the tibial base trial component14. As shown in FIG. 12, the fixation pins 250 include a posteriorfixation pin 252 that is sized to be received in either of the posteriorfixation pinholes 80 of the tibial base trial component 14 and ananterior fixation pin 254 that is sized to be received in either of theanterior fixation pinholes 82. Each of the fixation pins 252, 254includes a pin head 260 and a cylindrical shaft 262 that extends fromthe pin head 260 to a pointed conical tip 264 that is configured toengage the proximal end 402 of the patient's tibia 400. The shaft 262 ofthe pin 252 defines a length 266 that is shorter than a correspondinglength 268 defined by the shaft 262 of the pin 254. Additionally, in theillustrative embodiment, the shaft 262 of the pin 252 has a diameter 270that is smaller than a corresponding diameter 272 of the shaft 262 ofthe other pin 254.

As shown in FIG. 12, the pin head 260 of each of the pins 252, 254 has asimilar configuration. The pin head 260 includes an outer ring 280 andan inner ring 282 that is spaced apart from the outer ring 280. A groove284 is defined between the rings 280, 282. The rings 280, 282 have thesame diameter in size, which is greater than the diameters 270, 272 ofeither of the pins 252, 254. As described in greater detail below, thesurgeon positions a portion of a pin extraction tool 300 into the groove284 to manipulate the pins 252, 254.

As shown in FIG. 13, the pin extraction tool 300 includes an elongatedbody 302 that extends from a proximal end 304 to a distal end 306. Theextraction tool 300 also includes a lever arm 308 that is pivotallycoupled to the elongated body 302. A pair of opposing jaws 310, 312 aredefined on the distal ends of the elongated body 302 and lever arm 308,respectively. As described in greater detail below, the jaws 310, 312are configured to engage the pin heads 260 of the fixation pins 252,254.

The elongated body 302 includes an impaction plate 314 that ispositioned at the proximal end 304 and a grip 316 sized to receive ahand of a user. A longitudinal channel 318 is defined in the body 302,which is sized to receive the lever arm 308. The lever arm 308 includesa push button 320 that is positioned near the proximal end 304 of thebody 302, and the lever arm 308 is coupled to the elongated body 302 viaa locking pin 322. As shown in FIG. 13, the locking pin 322 defines anaxis of rotation 324 about which the lever arm 308 pivots to movebetween an engaged position (FIG. 14) in which the jaws 310, 312 capturea pin head 260 of one of the fixation pins 252, 254 and a disengagedposition (FIG. 15) in which the pin head 260 may be detached from thetool 300.

As shown in FIG. 14, the lower jaw 310 includes a distal face 330 of theelongated body 302. The distal face 330 is semi-circular and has anannular flange or lip 332 extending outwardly therefrom. A groove 334 isdefined between the face 330 and the lip 332, which is sized to receivethe outer ring 280 of fixation pin 252 or fixation pin 254. In theillustrative embodiment, the lip 332 extends over only a portion ofdistal face 330. As shown in FIG. 14, the lip 332 defines an arc that isless than 180 degrees.

The upper jaw 312 includes a distal face 340 of the lever arm 308. Thedistal face 340 is semi-circular and has an annular flange or lip 342extending outwardly therefrom. A groove 344 is defined between the face340 and the lip 342, which is sized to receive the outer ring 280 offixation pin 252 or fixation pin 254. In the illustrative embodiment,the lip 342 extends over the distal face 340 such that a pair of gaps346, 348 is defined between the lips 332, 342. As shown in FIG. 14, thelip 342 is semi-circular.

In use, a user may depress the push button 320 in the directionindicated by arrow 350 in FIG. 13 to actuate the lever arm 308. Thelever arm 308 may then pivot about the axis 324 to move the jaws 310,312 apart, as shown in FIG. 15. In the disengaged position shown in FIG.15, a surgeon may advance a pin head 260 between the jaws 310, 312 andmove the outer ring 280 into engagement with the lower lip 332 of thelower jaw 310. When the surgeon releases the push button 320, a springor other biasing member (not shown) causes the lever arm 308 to pivotback to the engaged position shown in FIG. 14, thereby advancing theupper lip 342 of the upper jaw 312 into engagement with the outer ring280 of the pin head 260. In that way, the jaws 310, 312 cooperate toprovide positive engagement with the pin head 260, and the fixation pinis retained in the extraction tool 300 and may be implanted or extractedfrom the patient's body.

Referring now to FIGS. 16-22, portions of an orthopaedic surgicalprocedure utilizing the system 10 are shown. The surgeon may firstperform a resection of the distal end 406 of the patient's femur 404 anda resection of the proximal end 402 of the patient's tibia 400 tosurgically prepare those ends for trial reduction and subsequentattachment of the knee prosthetic components. For example, as shown inFIG. 16, the surgically-prepared proximal end 402 of the patient's tibia400 includes a resected surface configured to receive the tibial basetrial component 14.

The surgeon may position the tibial base trial component 14 on theresected surface of the patient's tibia 400. The surgeon may then selectone of the tibial evaluation components 16 to be placed in the centralopening 40 of the tibial base trial component 14. If the surgeon desiresthe fixed bearing trial component 18, the surgeon may select thespikeless tibial evaluation component 136 and position it in the centralopening 40 by hand so that the inferior surface 184 of the tibialevaluation component engages the shelf surface 54 of the tibial basetrial component 14. If the surgeon desires a mobile bearing trialcomponent 18, the surgeon may select the spiked tibial evaluationcomponent 132. In some embodiments, the surgeon may use the spikedtibial evaluation component 132 for initial trial reduction before usingthe fixed tibial evaluation component 136. The use of mobile bearingtrial component and the spiked tibial evaluation component is furtherdescribed in co-pending U.S. patent application Ser. No. 14/265,960,entitled “TIBIAL TRIAL SYSTEM FOR A KNEE PROSTHESIS” by David Waite etal. and filed on Apr. 30, 2014.

In the illustrative embodiment, the surgeon may grip the selected tibialevaluation component 136 by the posterior buttress 170 and position itover the plate opening 30 of the tibial base trial component 14. Thesurgeon may then apply force in the direction indicated by arrow 410 tothe superior surface 182 of the evaluation component 136 to engage theinferior surface 184 of the tibial evaluation component 136 with theshelf surface 54 of the tibial base trial component 14, as shown in FIG.17.

Once the tibial evaluation component 136 is properly received in thecentral opening 40 of the tibial base trial component 14, the surgeonmay inferiorly advance a fixation pin 252 through one of the pinholes 80of the tibial base trial component 14 into the proximal end 402 of thepatient's tibia 400. When the posterior fixation pin 252 is properlyinserted into the tibial base trial component 14, a longitudinal axis264 of the posterior fixation pin 252 is perpendicular to the proximalsurface of the patient's tibia 400 and is relatively parallel to alongitudinal axis 266 of the patient's tibia 400. The posterior fixationpin 252 temporarily anchors one end of the tibial base trial component14 to the proximal end 402 of the patient's tibia 400. Inserting onlyone posterior fixation pin 252 in one of the posterior fixation pinhole80 permits the tibial base trial component 14 to rotate about thefixation pin 252 while the surgeon performs the trial reduction.

Once the posterior fixation pin 252 is properly inserted, the surgeonmay assemble a fixed bearing trial component 18 or a mobile bearingtrial component 18. The fixed bearing trial component 18 is shown inFIG. 17. As described above, the tibial bearing trial component 18 is amulti-piece assembly. Accordingly, a given tibial bearing trialcomponent 18 may be assembled with one of a number of tibial bearingsurface trial components 412 and one of a number of a plurality of trialshims 414, as shown in FIG. 22. In a single kit of trial components, thetibial bearing surface trial components 412 may be provided in differentsizes and/or configurations, and each trial shim 414 may have adifferent thickness. Because each trial shim 414 is configured to besecured to each tibial bearing surface trial component 412, the surgeonis able to assemble a tibial bearing trial component 18 of one size andconfiguration, evaluate the performance of that tibial bearing trialcomponent 18, and then modify the tibial bearing trial component 18 asnecessary to determine intraoperatively the type and configuration ofthe prosthetic tibial bearing component to be implanted.

The surgeon may assemble one of the trial shim 414 with one of thetibial bearing surface trial components 412 to form a tibial bearingtrial component 18. For example, the surgeon may select one of the fixedbearing surface trial components 412 and secure the trial shim 414thereto to form a fixed bearing trial component 18. During a surgicaltrialing procedure, the fixed bearing trial component 18 is advancedsuch that the post 126 of the posterior buttress 170 of the tibialevaluation component 16 is received in a central passageway 416 of thetrial shim 414. The trial shim 414 further includes two posteriorsidewalls 418, 420 which are configured to cooperate with the anteriorsidewalls 190, 194 of the arms 172, 174, respectively, of the posteriorbuttress 170 of the tibial evaluation component 136 to prevent the fixedtibial bearing trial component from rotating relative to the tibial basetrial component 14.

As shown in FIG. 18, the fixed bearing trial component 18 is selectedand the surgeon advances the posterior edge 422 of the assembled tibialbearing surface trial component 412 and trial shim 414 into the gapbetween the tibial base trial component 14 and the femoral trialcomponent 20. The shape of the posterior buttress 170 of the tibialevaluation component 136 allows the fixed bearing trial component 18 toadvance in the posterior direction between the tibial base trialcomponent 14 and the femoral trial component 20, as shown in FIGS.18-19. When the tibial bearing trial component 18 is seated between thetibial base trial component 14 and the femoral trial component 20, theposterior sidewalls 418, 420 of the trial shim 414 engage anteriorsidewalls 190, 194 of the arms 172, 174 of the posterior buttress 170 ofthe tibial evaluation component 136, respectively.

When the fixed bearing trial component 18 is in place, the surgeon mayperform the trial reduction. In doing so, the surgeon uses the system 10to evaluate and check the stability and kinematics of the patient'sfemur 404 and tibia 400 for implantation of a fixed bearing kneeprosthesis or a mobile bearing knee prosthesis. Particularly, thesurgeon carefully extends the knee of the patient, noting theanteroposterior stability, medial-lateral stability, and overallalignment in the anterior-posterior plane and medial-lateral plane.Rotational alignment of the tibial base trial component 14 relative tothe femoral trial component 20 may be adjusted with the knee in fullextension. The rotation of the tibial base trial component 14 is usuallycentered on the junction between the medial and central one-third of atibial tubercle.

As the range of motion is evaluated, a load on the femoral trialcomponent 20 translates posteriorly as the knee is moved betweenextension and flexion. To improve performance, the surgeon may removethe tibial bearing trial component 18 from the tibial base trialcomponent 14 to exchange the trial shim 414 and/or the tibial bearingsurface trial component 412. A removal tool (not shown) may be used todetach the tibial bearing trial component 18 from the tibial base trialcomponent 14. The surgeon may use a separator tool (not shown) to detachthe trial shim 414 from the tibial bearing surface trial component 412.The surgeon may then select another trial shim 414 having a differentthickness or choose a tibial bearing surface trial component 412 with analternative configuration, for example, a tibial bearing surface trialcomponent 412 that is cruciate retaining or posterior stabilized. Thesurgeon may continue to try various combinations of trial shim 414 andtibial bearing surface trial component 412 to ascertain which finalimplant will have the best stability in flexion and extension whilepermitting full extension. Once the revised combination of trial shim414 and tibial bearing surface trial component 412 is selected, the twocomponents are assembled to one another and anteriorly advanced in thegap between tibial base trial component 14 and the femoral trialcomponent 20 in the manner previously discussed.

Once the surgeon is satisfied with the trial reduction, without removingany of the trial components 12, the surgeon may inferiorly advance thefixation pin 254 through one of the pinholes 82 of the tibial base trialcomponent 14 and into the proximal end 402 of the patient's tibia 400.As described above, the anterior fixation pinhole 82 is positioned inthe center of the inclined surface 102 of the anterior tab 100 of thetibial base trial component 14. The anterior tab 100 extends from theanterior aspect 62 of the tibial base trial component 14, such that theanterior tabs 100 project outward from an anterior edge of the proximalend 402 of the patient's tibia 400, as shown in FIG. 18. The projectedanterior tab 100 is exposed throughout the trial reduction process toallow the surgeon to secure the anterior fixation pin 254 in theproximal end 402 of the patient's tibia 400 while the tibial bearingtrial components 18 and the femoral trial component 20 remain positionedon the tibial base trial component 14.

Unlike the posterior fixation pinhole 80, the anterior fixation pinhole82 is not positioned directly perpendicular to the proximal surface ofthe patient's tibia 400. Because an inferior surface 58 of the anteriortab 100 extends anteriorly outward from the anterior edge of theproximal end 402 of the patient's tibia 400, an anterior portion of theinferior surface 58 does not contact the proximal end 402 of thepatient's tibia 400. Accordingly, an inferior opening (not shown) of theanterior fixation pinhole 82 does not wholly rest on the proximal end402 of the patient's tibia 400. In order to secure the anterior fixationpin 254 in the proximal end 402 of the patient's tibia 400, the anteriorfixation pinhole 82 is designed so that when the anterior fixation pin254 is received in the anterior fixation pinhole 82, the longitudinalaxis 368 of the anterior fixation pin 254 is positioned at obliqueangles relative to the anterior surface of the proximal end 402 of thepatient's tibia. The position of the anterior fixation pinhole 82 allowsthe anterior fixation pin 254 to advance into the proximal end 402 ofthe patient's tibia 400 to further secure the tibial base trialcomponent 14 on the proximal end 402 of the patient's tibia 400. Afterperformance of the trial reduction, the surgeon may then continuesurgical preparation of the proximal end 402 of the patient's tibia 400.

Subsequently, the surgeon may utilize the keel punch 374 seated on thetibial base trial component 14 in the proximal end 402 of the patient'stibia 400 to enlarge the opening in the patient's tibia 400, as shown inFIG. 21. With the tibial base trial component 14 and a guide tower 370are positioned on the proximal end 402 of the patient's tibia 400, thesurgeon may use the tibial base trial component 14 and the guide tower370 to guide, for example, a surgical drill (not shown) while reamingthe proximal end 402 of the patient's tibia 400. Thereafter, the keelpunch 374 may be impacted into the proximal end 402 of the patient'stibia 400 before the guide tower 370 is removed, as shown in FIG. 21.

The keel punch 374 is configured to be inserted through the centralopening 40 of the tibial base trial component 14 into the proximal end402 of the patient's tibia 400 to prepare the patient's tibia 400 for aprosthetic component. The keel punch 374 has a base plate 376 having aperipheral rim 380 defined therein. The rim 380 has an inferior surface382 configured to engage the shelf surface 54 of the tibial base trialcomponent 14 when the keel punch 374 is seated on the tibial base trialcomponent 14. The base plate 376 also includes a central platform 384sized to be received in the central opening 40 of the tibial base trialcomponent 14, along with a pair of prongs 386 that extend laterallyoutward from the central platform 384. The prongs 386 are sized to bereceived in the elongated openings 42 of the tibial base trial component14. An exemplary procedure for reaming the patient's tibia 400 andinstalling the keel punch 374 is set forth in U.S. patent applicationSer. No. 13/530,945, entitled “METHOD OF SURGICALLY PREPARING A TIBIAFOR IMPLANTATION OF A PROSTHETIC COMPONENT” filed by David Waite et al.and filed on Jun. 28, 2012, which is incorporated herein by reference.

When the keel punch 374 is impacted into and removed from the proximalend 402 of the patient's tibia 400, the resulting proximal end 402 ofthe patient's tibia 400 includes an opening 408, as shown in FIG. 22.The surgeon may again repeat the trial reduction by assembling the fixedbearing trial component 18 or the mobile bearing trial component 18.This time, the surgeon may use the tibial evaluation component 138, 134with the sleeve 160, such that the sleeve 160 is received in the opening408 of proximal end 402 of the patient's tibia 400. For example, thesurgeon may choose to assemble one of the trial shims 414 with one ofthe fixed bearing surface trial components 412 to form a fixed bearingtrial component 18. The surgeon then positions the sleeve 160 of thetibial evaluation component 138 into the opening 408 of proximal end 402of the patient's tibia 400. The surgeon subsequently places the fixedbearing trial component 18 over the tibial base trial component 14, suchthat the post 126 is received in the central passageway 416 of the trialshim 414 and the posterior sidewalls 418, 420 of the trial shim 414engages anterior sidewalls 190, 194 of the arms 172, 174 of theposterior buttress 170 of the tibial evaluation component 138,respectively.

The surgeon may then repeat the trial reduction until satisfied with thealignment and the stability of the knee. When the additional trialreduction is complete, the surgeon may use the impaction handle 372 toremove the keel punch 374 from the patient's tibia 400. The surgeon mayfurther use the pin extraction tool 300 to extract the posteriorfixation pin 252 and/or the anterior fixation pin 254 from the patient'stibia 400. The resultant features surgically formed in the proximal end402 of the patient's tibia 400 are configured to receive a tibial trayof a fixed bearing knee prosthesis or a mobile bearing knee prosthesis.The surgeon then completes the surgical procedure of the remainingcomponents of the prosthesis.

Alternatively or additionally, as shown in FIG. 22, the surgeon maychoose to assemble one of the trial shims 414 with one of the mobilebearing surface trial components 412 to form a mobile bearing trialcomponent 18. The surgeon may then position the sleeve 160 of the tibialevaluation component 134 into the opening 408 of proximal end 402 of thepatient's tibia 400 and place the mobile bearing trial component 18 overthe tibial base trial component 14. The surgeon may then move thepatient's leg between flexion and extension to evaluate the range ofmotion. As described above, the configuration of the evaluationcomponent 134 permits the mobile bearing trial component 18 to rotaterelative to the patient's tibia as the leg is moved between flexion andextension. It should be appreciated that in other embodiments the trialshim 414 may be positioned on the tibial base trial 14 prior toattaching the bearing surface trial 412 thereto.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. An orthopaedic surgical instrument system for use during a surgicalprocedure to implant an orthopaedic knee prosthesis, comprising: atibial base trial component adapted to be positioned on asurgically-prepared proximal end of a patient's tibia, the tibial basetrial component having an opening defined therein, an insert componentshaped to be received in the opening defined in the tibial base trialcomponent, the insert component comprising a base plate, and a generallyY-shaped posterior buttress extending upwardly from a superior surfaceof the base plate, and a tibial bearing trial component having an innersidewall that defines an opening therein, wherein the posterior buttressof the insert component is configured to be received in the opening ofthe tibial bearing trial component to prevent rotation of the tibialbearing trial component relative to the tibial base trial component. 2.The orthopaedic surgical instrument system of claim 1, wherein theposterior buttress includes a post positioned adjacent to a posterioredge of the base plate and a pair of arms extending posteriorly from thepost and outwardly from the posterior edge of the base plate.
 3. Theorthopaedic surgical instrument system of claim 2, wherein: the pair ofarms includes a first arm and a second arm, and a first imaginary lineextends along a lateral-most edge of the first arm of the posteriorbuttress, a second imaginary line extends along a medial-most edge ofthe second arm of the posterior buttress and intersects the firstimaginary line to define an angle of intersection therebetween, theangle of intersection being between 45-145°.
 4. The orthopaedic surgicalinstrument system of claim 1, wherein the insert component furthercomprises an anterior buttress extending outwardly from an anterior edgeof the base plate.
 5. The orthopaedic surgical instrument system ofclaim 4, wherein the anterior buttress includes (i) a pair of armsextending anteriorly from the anterior edge of the base plate and (ii) atab extending superiorly from an anterior end of each arm.
 6. Theorthopaedic surgical instrument system of claim 1, further comprising aretention mechanism to secure the insert component to the tibial basetrial component.
 7. The orthopaedic surgical instrument system of claim6, wherein the retention mechanism comprises: an annular rim extendingoutwardly from the base plate of the insert component, and a groovedefined in the tibial base trial component sized to receive the annularrim of the insert component.
 8. The orthopaedic surgical instrumentsystem of claim 1, wherein the insert component includes a first prongextending medially from the base plate and a second prong extendinglaterally from the base plate.
 9. The orthopaedic surgical instrumentsystem of claim 1, wherein the insert component includes a keelconfigured to extend inferiorly and outwardly from the opening in thetibial base trial component when the insert component is received in theopening defined in the tibial base trial component.
 10. The orthopaedicsurgical instrument system of claim 1, wherein: the tibial base trialcomponent includes an inferior surface positioned opposite the superiorsurface, the opening in the tibial base trial component is defined by aninner wall extending inwardly from the superior surface to a shelfsurface positioned between the superior surface and the inferiorsurface, and a number of fixation pinholes extend through a posteriorsection of the shelf surface and the inferior surface.
 11. Theorthopaedic surgical instrument system of claim 10, further comprising afixation pin including: a head including (i) an inferior surfaceconfigured to engage the posterior section of the shelf surface and (ii)a superior surface positioned opposite the inferior surface, and a shaftextending from the inferior surface of the head, wherein when theinferior surface of the head of the fixation pin is engaged with theposterior section of the shelf surface, the superior surface of the headof the fixation pin is configured to be positioned at or below animaginary plane defined by the superior surface of the tibial base trialcomponent and the shaft is sized to extend inferiorly from at least oneof the fixation pinholes defined in the tibial base trial component. 12.The orthopaedic surgical instrument system of claim 11, furthercomprising: a pin extraction tool comprising (i) a stationary member,(ii) a pivoting member pivotally coupled to the handle, and (iii) areceiving end including a first jaw extending from the stationary memberand a second jaw extending from the pivoting member, the first jaw andthe second jaw being configured to engage the head of the fixation pin,wherein the pivoting member is pivotable between (i) a closed positionin which the first jaw and the second jaw define a pocket sized toretain the head of the fixation pin, and (ii) an open position in whichthe first jaw and the second jaw are spaced apart to permit the head ofthe fixation pin to be disengaged from the first jaw and the second jaw.13. The orthopaedic surgical instrument system of claim 1, wherein theinsert component is a first insert component, and the system furthercomprises a second insert component configured to be separately receivedin the opening defined in the tibial base trial component in place ofthe first insert component, the second insert component having a centralpost, wherein a superior surface of the central post has a ramp surfacedefined therein, the ramp surface inclines superiorly in ananterior-to-posterior direction.
 14. An orthopaedic surgical instrumentsystem for use during a surgical procedure to implant an orthopaedicknee prosthesis, comprising: a tibial base trial component including (i)a superior surface, (ii) an inferior surface positioned opposite thesuperior surface that is adapted to be positioned on asurgically-prepared proximal end of a patient's tibia, (iii) an openingbeing defined by an inner wall extending inwardly from the superiorsurface to a shelf surface positioned between the superior surface andthe inferior surface, and (iv) a fixation pinhole extending through aposterior section of the shelf surface and the inferior surface of thetibial base trial component, a fixation pin including a head and a shaftextending inferiorly from the head that is sized to be received in thefixation pinhole of the tibial base trial component, an insert componentshaped to be received in the opening defined in the tibial base trialcomponent, and a tibial bearing trial component adapted to be positionedon the insert component, wherein the head of the fixation pin is sizedto be at or below the superior surface of the tibial base trialcomponent when the head is engaged with the shelf surface.
 15. Theorthopaedic surgical instrument system of claim 14, further comprising asurgical instrument including a pair of jaws configured to selectivelyengage the head of the fixation pin, the pair of jaws comprising a firstjaw including a semi-circular flange and a second jaw including an arcedflange extending less than 180 degrees.